There are two different tools to use if you want to use the references in your RefWorks account while writing: one for citing in Microsoft Word and one for citing in Google Docs. Both are downloaded/installed from the tools menu from within your RefWorks account.
You can also use the Tools menu to check for duplicates - it is important not to have any duplicate references in your library.
To share a folder of references with another RefWorks user, first create the folder in your RefWorks account. Then select the folder in the menu "Sharing" and invite another RefWorks user to share it with you. You can choose if you want the other user to be able to read, annotate or modify in the folder. If you want the other user to be able to add new references to the folder, select "Can modify".
RefWorks has a plugin for writing, which works in Microsoft Word. To download it, login to your RefWorks account and choose Tools --> Cite in Microsoft Word. Make sure you know which version of Word your are using!
You need to have Java installed on your computer. If you are using Mac Yosemite (OS X 10.10) or El Capitan (OS X 10.11), you should install Java 6 and not the latest version - find it here. If you are using Word 2016, download the Refworks Citation Manager from your Word Store.
If you are using Word 2016 on Mac, you have to use the "RefWorks Citation Manager", which is available through your Word software. Open a document, go to the menu "Insert tab > Add-ins > Word Store and search for RefWorks. Then select the RefWorks Citation Manager and add it to your Word.
Once you have the plugin/add-in installed, login to your RefWorks account from Word. You can use all the references you have in your account to cite while you are writing.
RefWorks has an add-on for writing in Google Docs, which allows you to cite your references and create a bibliography while writing in Google Docs. To download it, login to your RefWorks account and choose Tools --> Cite in Google Docs.
Once you have the add-on installed, login to your RefWorks account from Google Docs to use all of the references from your Refworks account.